1. Field of Invention
The present invention relates generally to a method and apparatus for fuel cell packaging and, more specifically, to a method and apparatus for fuel cell packaging employing a receptacle shaped to receive fuel cells in a staggered or spiral configuration.
2. Description of the Related Art
Fuel cells such as, the Proton Exchange Membrane (“PEM”) fuel cell include a membrane electrode assembly (“MEA”). The MEA comprises a solid polymer electrolyte or ion exchange membrane positioned between an anode and a cathode which typically comprise finely divided carbon particles, very finely divided catalytic particles supported on the internal and external surfaces of the carbon particles, and proton conductive material intermingled with the catalytic and carbon particles.
The catalytic particles, e.g., finely comminuted platinum, at each membrane/electrode interface induce the desired electrochemical reaction. On the anode side, the fuel (e.g., hydrogen) permeates the porous electrode material and reacts with the catalytic particles to form hydrogen cations (e.g., protons) which migrate through the ion exchange membrane to the cathode side. On the cathode side, the oxidant (e.g., gas containing oxygen) reacts with the catalytic particles to form oxygen anions. At the cathode, the anions react with the cations to complete the electrochemical reaction and form a reaction product (e.g., liquid water).
In conventional fuel cells, the MEA is positioned between a pair of electrically conductive elements, typically plates, which serve as current collectors for the anode and cathode. The plates are often formed with channels to facilitate the distribution of the aforementioned gaseous reactants over the anode and cathode catalyst surfaces. When a plurality of fuel cells are configured as a stack to form a series electrical connection between them, the plates provide the electrical connection and are often referred to as bipolar plates. In such a configuration, each bipolar plate conducts current between the anode of one cell to the cathode of the adjacent cell in the stack.
A problem with conventional fuel cell stacks is that the periphery of each fuel cell usually includes manifolds and seals which increase the size and therefore the cost of the fuel cells. Thus, a need exists for a fuel cell packaging approach which would allow for a reduction in the size of the periphery portion of the fuel cells.
Another problem with conventional fuel cell packaging approaches is that they typically include molded rubber fluid interfaces to the fuel cells which are prone to leakage. Thus, a need exists for a fuel cell packaging approach which would provide improved fluid interfaces for the fuel cells.
Another problem with conventional fuel cell packaging approaches is that it is often difficult to disassemble and reassemble the packaging to replace individual fuel cells, perform diagnostic tests, etc. Thus, a need exists for a fuel cell packaging approach which would facilitate a simple, accurate and repeatable procedure for assembling or disassembling a fuel cell stack.